The southward expansion of East Asian farmers profoundly influenced the social evolution of Southeast Asia by introducing cereal agriculture.However,the timing and routes of cereal expansion in key regions are unclear...The southward expansion of East Asian farmers profoundly influenced the social evolution of Southeast Asia by introducing cereal agriculture.However,the timing and routes of cereal expansion in key regions are unclear due to limited empirical evidence.Here we report macrofossil,microfossil,multiple isotopic(C/N/Sr/O)and paleoproteomic data directly from radiocarbon-dated human samples,which were unearthed from a site in Xingyi in central Yunnan and which date between 7000 and 3300 a BP.Dietary isotopes reveal the earliest arrival of millet ca.4900 a BP,and greater reliance on plant and animal agriculture was indicated between 3800 and 3300 a BP.The dietary differences between hunter-gatherer and agricultural groups are also evident in the metabolic and immune system proteins analysed from their skeletal remains.The results of paleoproteomic analysis indicate that humans had divergent biological adaptations,with and without farming.The combined application of isotopes,archaeobotanical data and proteomics provides a new approach to documenting dietary and health changes across major subsistence transitions.展开更多
Deep and ultra-deep reservoirs have dense matrix and high fracture pressure, which leads to high pressure and difficulty in fracturing construction. Conventional aggravated fracturing fluids have the problems of low a...Deep and ultra-deep reservoirs have dense matrix and high fracture pressure, which leads to high pressure and difficulty in fracturing construction. Conventional aggravated fracturing fluids have the problems of low aggravation efficiency, high friction resistance, etc., and the reduction of construction pressure cannot reach the theoretical effect. In view of the above problems, this paper adopts the weighting agent HD160 and the drag reducing agent JHFR-2 to form a new type of weighted slippery water fracturing fluid system. And the weighting performance, drag reduction performance, corrosion performance, anti-expansion performance and reservoir damage of this system were studied. The results show that the density of the system is adjustable within 1.1 - 1.6 g·cm−3, and the drag reduction rate can be up to 68% at 1.5 g·cm−3, with low corrosion rate, surface tension less than 28 mN·m−1, anti-expansion rate as high as 94.5%, and the damage rate of the reservoir permeability is less than 10%, which is of good application prospect.展开更多
基金the Second Tibetan Plateau Scientific Expedition and Research Program(2019QZKK0601)the Priority Research Program of the Chinese Academy of Sciences(XDA2004010101)+6 种基金the National Natural Science Foundation of China(42271160,32060208,31801040,and 32270667)the Major Project of National Social Science Foundation of China(21&ZD285and 20&ZD248)the National Key Research&Development Program of China(2020YFE0202200)Westlake Education FoundationNanqiang Outstanding Young Talents Program of Xiamen University(X2123302)the European Research Council Grant(ERC-2019-ADG-883700-TRAM)the Academician and Expert Workstation of Yunnan Province(202305AF150183)。
文摘The southward expansion of East Asian farmers profoundly influenced the social evolution of Southeast Asia by introducing cereal agriculture.However,the timing and routes of cereal expansion in key regions are unclear due to limited empirical evidence.Here we report macrofossil,microfossil,multiple isotopic(C/N/Sr/O)and paleoproteomic data directly from radiocarbon-dated human samples,which were unearthed from a site in Xingyi in central Yunnan and which date between 7000 and 3300 a BP.Dietary isotopes reveal the earliest arrival of millet ca.4900 a BP,and greater reliance on plant and animal agriculture was indicated between 3800 and 3300 a BP.The dietary differences between hunter-gatherer and agricultural groups are also evident in the metabolic and immune system proteins analysed from their skeletal remains.The results of paleoproteomic analysis indicate that humans had divergent biological adaptations,with and without farming.The combined application of isotopes,archaeobotanical data and proteomics provides a new approach to documenting dietary and health changes across major subsistence transitions.
文摘Deep and ultra-deep reservoirs have dense matrix and high fracture pressure, which leads to high pressure and difficulty in fracturing construction. Conventional aggravated fracturing fluids have the problems of low aggravation efficiency, high friction resistance, etc., and the reduction of construction pressure cannot reach the theoretical effect. In view of the above problems, this paper adopts the weighting agent HD160 and the drag reducing agent JHFR-2 to form a new type of weighted slippery water fracturing fluid system. And the weighting performance, drag reduction performance, corrosion performance, anti-expansion performance and reservoir damage of this system were studied. The results show that the density of the system is adjustable within 1.1 - 1.6 g·cm−3, and the drag reduction rate can be up to 68% at 1.5 g·cm−3, with low corrosion rate, surface tension less than 28 mN·m−1, anti-expansion rate as high as 94.5%, and the damage rate of the reservoir permeability is less than 10%, which is of good application prospect.
基金supported by the Innovation Program for Quantum Science and Technology(2021ZD0302800)the National Natural Science Foundation of China(11904350,12174362)+3 种基金Anhui Provincial Natural Science Foundation(2008085QA30)Shenzhen Science and Technology Program(KQTD20190929173815000)Guangdong Innovative and Entrepreneurial Research Team Program(2019ZT08C044)the National Synchrotron Radiation Laboratory(KY2060000177).
